Peripheral arterial disease is the most common form of atherosclerosis that affects many people worldwide. As a result of such disease, many people experience pain during walking. Such condition may be treated medically with exercise and drugs, such as Cilostazol, which modestly improves walking ability by inhibition of platelet aggregation. However, in many cases, patients do not follow the prescribed exercise therapy because of pain associated with the disease. Other types of drugs have also been used to treat ischemia, but many of these drugs have side effects.
Medical interventions such as balloon angioplasty, stenting, and surgery are options to treat patients who are suffering from peripheral arterial diseases and critical limb ischemia. However, many of such procedures may fail. Consequences of graft failure include continued ischemia, poor wound healing, gangrene, or amputation of a patient's limb.
Ultrasound devices have been used to diagnose patients. For example, ultrasonic energy may be employed to obtain images of a part of a patient during a diagnostic procedure. In addition, ultrasound systems have been used for treating tissue, e.g., by directing acoustic energy towards a target tissue region within a patient, such as a cancerous or benign tumor, to heat the tissue region. For example, an ultrasound transducers may be disposed adjacent a patient's body and operated (generally at a frequency that is in the megahertz range) to deliver high intensity acoustic waves, such as ultrasonic waves, at an internal tissue region of a patient to heat the tissue region, thereby injuring target tissue at the tissue region.